1. Field of the Invention
The present invention relates to a temperature controlled environment for a passenger cabin for a vehicle. More particularly, the present invention relates to a temperature controlled passenger cabin environment that has a number of thermo-electric heat pumps for providing additional heating to the passenger cabin (for when waste heat from the engine is insufficient) and/or cooling the passenger cabin.
2. Description of the Related Art
Temperature control systems are known in the art for passenger cabins. Such known systems use a vapor compression cycle to provide cooling. A compressor is connected to an engine and circulates refrigerant that feeds a condenser. The condensed refrigerant is then throttled and used to provide cooling to the driver and at an evaporator in the main cabin.
For buses, engine waste heat is transferred to a fluid and circulated around the passenger cabin to provide heating. Furthermore, when desired additional heaters may be provided. Such heaters are, in some instances, a diesel fired auxiliary heater. This auxiliary heater and waste heat generated by the engine warm the passenger compartment.
However, these two systems are costly to install and are bulky. This bulk increases the overall weight of the vehicle. The increase in weight also tends to lessen the fuel economy of the vehicle. Moreover, such systems may heat the passenger cabin unevenly thus causing discomfort to some because the passenger cabin is too hot, not hot enough or too cold at certain areas.
Further, the vapor compression cycle uses a refrigerant. Such refrigerants are costly and also are very disfavored. Some refrigerants are well known and are very harmful to the environment and require increased service costs for safe removal from the vapor compression cycle, and for replacement.
Accordingly, there is a need for a cooling system for a passenger cabin that does not use any refrigerant, and does not have any vapor compression cycle. There is also a need for a temperature control system for a passenger cabin that does not use any additional heating device. There is still another need for a system for a passenger cabin that modulates the temperature at a number of preselected points in the passenger cabin for a more comfortable operation.
There is also a need for such a system that eliminates one or more of the aforementioned drawbacks and deficiencies of the prior art.